In a way similar to an optical communication system on land, a submarine cable system is also required to be capable of flexibly changing a configuration of a network, and to be robust against disaster. Thus, a submarine cable system is also requested to achieve an optical branching/coupling device including a wavelength switching function (ROADM function) being capable of remotely controlling, by use of a wavelength selective switch (WSS) used in a land system, setting of a communication system after start of operation. WSS is an abbreviation of wavelength selective switch, and ROADM is an abbreviation of reconfigurable optical add/drop multiplexing (a resettable optical branching/coupling function).
In relation to the present invention, PTL 1 describes a technique for achieving a network system by disposing a wavelength cross-connect (WXC) device in a node.